Infant drinking devices are generally known. Such devices often include an aerator. This allows the entry of atmospheric air back into the bottle, as the infant drinks fluid from the device and creates an underpressure inside the reservoir. The underpressure inside the reservoir causes the aerator or valve to open. The aerator thereto has an opening, which is for instance created by cutting a slit in flexible material of the aerator through which opening air can pass to overcome the effects of negative pressure inside the reservoir. On the one hand the opening should ensure that air can pass to the inside of the reservoir as explained here before, but on the other hand leakage of fluid from the reservoir to the outside of the device should be avoided as much as possible. Another known problem of such drinking devices is that the aerator may become stuck quite easily, thereby compelling the caretaker to intervene and clear up the aerator. This may be a rather tiresome clean-up chore, especially when the reservoir is still filled and the inside of the teat being moisturized with liquid. The intervention of the caretaker may also influence the hygienically prepared milk or other fluid negatively. Besides it is inconvenient for the baby who cannot extract milk or any other fluid from the bottle anymore, as air inflow in the bottle is prevented by the stuck valve and as the teat has to be removed from his mouth thereafter by the caretaker to clear up the aerator. When the teat blocks or is removed from the baby's mouth, many babies start crying. This makes parents often nervous.
EP 1 863 427 A1 discloses a teat for a feeding bottle having a one-way valve located in the skirt of the teat to allow to enter the feeding bottle to replace liquid sucked out of the bottle through the nipple while preventing liquid from leaking from the bottle.